Various types of fiber optic connections between adapters and plugs are known, including screw lock types, bayonet locks and the push-on lock type also known as push-pull coupling type. Umeki, et al, Japanese Showa 60-218932 discloses a push-pull coupling type. It includes an adapter equipped with an alignment sleeve and resilient catch pieces. The pieces are in cantilever form with protrusions and a claw attached to the tip of the form. The connector also includes a frame that contains an integrated ferrule and a through passageway from the rear to the front of the ferrule The frame has protruding parts that are caught by claws of the resilient catch pieces of the adapter. A resilient inner tube shaped in the form of a round tube has an inside diameter almost equal to the outside diameter of the optical fiber cable and an outside diameter almost equal to the hole in the rear portion of the plug frame. A cord tube has a flexible part at its front end which, when inserted into the hole in the rear of the plug frame, is secured to the frame by the bending of the flexible part The plug frame also has a finger grip mounted on its outside with raised parts. When the ferrule of the plug frame is inserted into or pulled from the alignment sleeve, the raised parts of the plug frame contact the protrusions of the cantilever form and push the resilient claws to the outside allowing the protrusions to pass. The plug frame may have a finger grip housing which is able to slide forward and backward with respect to the plug frame and, additionally, which has raised parts which release the catch of claws on the protruding parts of the plug frame when the finger grip housing is moved backward.
Other connectors of the push-pull coupling type are disclosed by Iwasa, et al, Japanese Showa 62-26141; Myers, et al, U.S. Pat. No. 4,872,736; and co-pending application Ser. No. 07/491,755, filed Mar. 9, 1990.
Co-pending U.S. patent application Ser. No. 07/491,755 refers to Gerace, et al, U.S. patent application Ser. No. 07/159,151, published EPC Specification No. 0330399, Aug. 30, 1989, which relates to a sheath connector for an optical fiber. This connector may be adapted to a push-pull type connector by a plug housing in two sections with biasing surface and slot for mating with resilient catch pieces of an adapter as taught by co-pending application Ser. No. 07/491,755, filed Mar. 9,1990. The optical fiber connector of Gerace, which is adapted to a push-pull type connector by a plug housing, includes a shell and at least one reciprocating holder in the shell for holding the optical fiber. The optical fiber is connected to the reciprocating holder and is slidable within its load bearing portion with the load bearing portion anchored to the shell. The fiber is reciprocable together with the reciprocating holder and is reciprocable with respect to the shell and the load bearing portion. The connector further includes a sheath for the optical fiber on the reciprocating holder with the optical fiber extending along the sheath.
In assembling the connectors of push-pull coupling type, the optical fiber cable is passed successively through the interiors of a strain relief boot and a crimp ferrule and adhesive is then deposited into the body of the holder. The adhesive may be injected by a syringe. With the Gerace, et al, type of sheath connector, the needle is introduced into an end portion of the sheath which has been cut at an angle to provide an enlarged eliptical mouth. The rear portion of the sheath projects outwardly from the anchoring portion of the connector shell and sheaths the needle during entry and withdrawal. The adhesive is deposited near the front end of the connector body adjacent the alignment ferrule and remote from the open rear-end of the sheath. The sheath prevents leaking of the adhesive from the holder and prevents the adhesive from spreading over the spring and the shell. Following withdrawal of the needle, the alignment ferrule is pressed against a stationary surface, for example a table, causing the holder to be slidable displaced compressing a coil spring. Then with biasing of the spring, the ferrule and associated optical fiber extend somewhat forward of the face of the connector with the fiber end extending somewhat forward of the ferrule. This extending portion of the fiber must be handled delicately Any untoward movement from forces applied through mishandling will cause the fiber end to shift, unseating it from its fit within the connector, causing damage to the fiber body, and making it unsuitable for use or even causing the fiber to break requiring that the connector be reterminated. Hence, at this point a fiber protector is installed over the ferrule/fiber end portion and the protector attached to the end of connector. The connector is then hung with tip down and is heated in a curing oven at, for example, 65.degree. C. for four hours, with the protector acting as a splint to the fiber end and ferrule.
Use of conventional fiber protectors for attachment to connectors of push-pull types to cover the ferrule/fiber has not been satisfactory because a firm and encompassing fit has not been obtainable Poor fit oftentimes results in failure to protect the fiber end portion from unseating from the ferrule or from damage or breakage of the fiber itself and in some cases, a poor fitting protector itself contributes to the damage and breaking. The present invention relates to a fiber protector having characteristics that result in an improved and secure fit to fiber end and to ferrule of optical connectors. Particularly the fiber protector provides improved protection during the curing of connectors generally of the push-pull coupling type.